Hyperglycemia
A condition of abnormally high blood glucose levels.
Hyperglycemia is a medical condition characterized by an unusually high amount of glucose in the blood. It is defined as a blood glucose level exceeding 6.9 mmol/L (125 mg/dL) after fasting for 8 hours or 10 mmol/L (180 mg/dL) 2 hours after eating. Chronic hyperglycemia is the defining characteristic of diabetes mellitus and can lead to serious complications over time, while acute severe hyperglycemia is a medical emergency.
Quick Facts
- Field
- Endocrinology
- Symptoms
- Increased hunger and thirst · polyuria · blurred vision · fatigue · dry mouth · dry or itchy skin
- Complications
- Hyperinsulinemia · ketoacidosis · hyperosmolar hyperglycemic state · seizures · coma
Facts from the source article.
Lore & Background
Hyperglycemia may be asymptomatic, with blood glucose levels rising above normal without producing permanent effects or symptoms for significant periods. The degree of hyperglycemia can change over time depending on metabolic causes such as impaired glucose tolerance or fasting glucose, and it can depend on treatment. Symptoms associated with acute or chronic hyperglycemia include the classic triad of polyphagia (frequent hunger), polydipsia (excessive thirst), and polyuria (increased volume of urination), as well as blurred vision, fatigue, restlessness, weight loss or gain, poor wound healing, dry mouth, dry or itchy skin, tingling in feet or heels, erectile dysfunction, recurrent infections, delayed gastric emptying, cardiac arrhythmia, stupor, coma, and seizures.
Reader's Guide
Hyperglycemia is significant primarily as the defining characteristic of diabetes mellitus, but it also occurs in various non-diabetic endocrine disorders, sepsis, intracranial diseases, and stress. Chronic hyperglycemia over years can produce serious complications including kidney damage, neurological damage, cardiovascular damage, damage to the retina, damage to feet and legs, diabetic neuropathy, impairment of growth, and susceptibility to certain infections. Acute severe hyperglycemia is a medical emergency that can rapidly produce complications such as fluid loss through osmotic diuresis and ketoacidosis. Hyperglycemia also injures the heart even in patients without a history of heart disease or diabetes and is strongly associated with heart attacks and death. Additionally, hyperglycemia has been linked to increased susceptibility to infectious diseases, including tuberculosis, the flu, and COVID-19, due to impairment of the immune system's response, particularly affecting neutrophil function. Postprandial hyperglycemic levels as high as 8.6 mmol/L (155 mg/dL) at 1 hour are associated with type 2 diabetes mellitus-related complications, which worsen as the degree of hyperglycemia increases.
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